Click Captcha

The Click CAPTCHA requires users to click specified points or characters on the main image, ideal for quick verification scenarios. It supports two modes:

• Text Mode：Displays characters (e.g., letters, numbers, or Chinese characters), and users click the corresponding characters.
• Graphic Mode：Displays graphics (e.g., icons or shapes), and users click the corresponding graphics.

How It Works

1. Generate Main Image (masterImage): Contains randomly distributed points or characters, typically in JPEG format.
2. Generate Thumbnail (thumbImage): Displays the target points or characters to be clicked, typically in PNG format.
3. User Interaction: Users click coordinates on the main image, and the frontend captures and sends the coordinates to the backend.
4. Verification Logic: The backend compares the clicked coordinates with the target points (dots) to verify a match.

Install Module

$ go get -u github.com/wenlng/go-captcha/v2@latest

$ go get -u github.com/wenlng/go-captcha/v2@latest

Install assets

$ go get -u github.com/wenlng/go-captcha-assets@latest

$ go get -u github.com/wenlng/go-captcha-assets@latest

Example

package main

import (
	"encoding/json"
	"fmt"
	"log"

	"github.com/golang/freetype/truetype"
	"github.com/wenlng/go-captcha-assets/bindata/chars"
	"github.com/wenlng/go-captcha-assets/resources/fonts/fzshengsksjw"
	"github.com/wenlng/go-captcha-assets/resources/imagesv2"
	"github.com/wenlng/go-captcha/v2/base/option"
	"github.com/wenlng/go-captcha/v2/click"
)

var textCapt click.Captcha

func init() {
  builder := click.NewBuilder()

  // fonts
	fonts, err := fzshengsksjw.GetFont()
	if err != nil {
		log.Fatalln(err)
	}

	// background images
	imgs, err := imagesv2.GetImages()
	if err != nil {
		log.Fatalln(err)
	}

	builder.SetResources(
		click.WithChars(chars.GetChineseChars()),
		click.WithFonts([]*truetype.Font{fonts}),
		click.WithBackgrounds(imgs),
	)
	
	textCapt = builder.Make()
}

func main() {
	captData, err := textCapt.Generate()
	if err != nil {
		log.Fatalln(err)
	}

	dotData := captData.GetData()
	if dotData == nil {
		log.Fatalln(">>>>> generate err")
	}

	dots, _ := json.Marshal(dotData)
	fmt.Println(">>>>> ", string(dots))

  var mBase64, tBase64 string
	mBase64, err = captData.GetMasterImage().ToBase64()
	if err != nil {
		fmt.Println(err)
	}
	tBase64, err = captData.GetThumbImage().ToBase64()
	if err != nil {
		fmt.Println(err)
	}

	fmt.Println(">>>>> ", mBase64)
	fmt.Println(">>>>> ", tBase64)
	
	// err = captData.GetMasterImage().SaveToFile("./.caches/master.jpg", option.QualityNone)
	// if err != nil {
	// 	fmt.Println(err)
	// }
	// err = captData.GetThumbImage().SaveToFile("./.caches/thumb.png")
	// if err != nil {
	// 	fmt.Println(err)
	// }
}

package main

import (
	"encoding/json"
	"fmt"
	"log"

	"github.com/golang/freetype/truetype"
	"github.com/wenlng/go-captcha-assets/bindata/chars"
	"github.com/wenlng/go-captcha-assets/resources/fonts/fzshengsksjw"
	"github.com/wenlng/go-captcha-assets/resources/imagesv2"
	"github.com/wenlng/go-captcha/v2/base/option"
	"github.com/wenlng/go-captcha/v2/click"
)

var textCapt click.Captcha

func init() {
  builder := click.NewBuilder()

  // fonts
	fonts, err := fzshengsksjw.GetFont()
	if err != nil {
		log.Fatalln(err)
	}

	// background images
	imgs, err := imagesv2.GetImages()
	if err != nil {
		log.Fatalln(err)
	}

	builder.SetResources(
		click.WithChars(chars.GetChineseChars()),
		click.WithFonts([]*truetype.Font{fonts}),
		click.WithBackgrounds(imgs),
	)
	
	textCapt = builder.Make()
}

func main() {
	captData, err := textCapt.Generate()
	if err != nil {
		log.Fatalln(err)
	}

	dotData := captData.GetData()
	if dotData == nil {
		log.Fatalln(">>>>> generate err")
	}

	dots, _ := json.Marshal(dotData)
	fmt.Println(">>>>> ", string(dots))

  var mBase64, tBase64 string
	mBase64, err = captData.GetMasterImage().ToBase64()
	if err != nil {
		fmt.Println(err)
	}
	tBase64, err = captData.GetThumbImage().ToBase64()
	if err != nil {
		fmt.Println(err)
	}

	fmt.Println(">>>>> ", mBase64)
	fmt.Println(">>>>> ", tBase64)
	
	// err = captData.GetMasterImage().SaveToFile("./.caches/master.jpg", option.QualityNone)
	// if err != nil {
	// 	fmt.Println(err)
	// }
	// err = captData.GetThumbImage().SaveToFile("./.caches/thumb.png")
	// if err != nil {
	// 	fmt.Println(err)
	// }
}

Reference

Create an instance

• builder.Make()
• builder.MakeWithShape()

Configure

TIP

click.NewBuilder(click.WithXxxx(), click.WithXxxx(), ....) OR builder.SetOptions(click.WithXxxx(), click.WithXxxx(), ....)

• click.WithImageSize(option.Size)

• click.WithRangeLen(option.RangeVal)

• click.WithRangeAnglePos([]option.RangeVal)

• click.WithRangeSize(option.RangeVal)

• click.WithRangeColors([]string)

• click.WithDisplayShadow(bool)

• click.WithShadowColor(string)

• click.WithShadowPoint(option.Point)

• click.WithImageAlpha(float32)

• click.WithUseShapeOriginalColor(bool)

• click.WithThumbImageSize(option.Size)

• click.WithRangeVerifyLen(option.RangeVal)

• click.WithDisabledRangeVerifyLen(bool)

• click.WithRangeThumbSize(option.RangeVal)

• click.WithRangeThumbColors([]string)

• click.WithRangeThumbBgColors([]string)

• click.WithIsThumbNonDeformAbility(bool)

• click.WithThumbBgDistort(int) option.DistortLevel1 (1-5)

• click.WithThumbBgCirclesNum(int)

• click.WithThumbBgSlimLineNum(int)

Resources

TIP

builder.SetResources(click.WithXxxx(), click.WithXxxx(), ....)

• click.WithChars([]string)
• click.WithShapes(map[string]image.Image)
• click.WithFonts([]*truetype.Font)
• click.WithBackgrounds([]image.Image)
• click.WithThumbBackgrounds([]image.Image)

Captcha Data

• GetData() map[int]*Dot
• GetMasterImage() imagedata.JPEGImageData
• GetThumbImage() imagedata.PNGImageData

Image instance

TIP

In the captcha data generated by generate method, the images are in JPEG and PNG formats respectively

JPEGImageData

• Get() image.Image
• ToBytes() ([]byte, error)
• ToBytesWithQuality(imageQuality int) ([]byte, error)
• ToBase64() (string, error)
• ToBase64Data() (string, error)
• ToBase64WithQuality(imageQuality int) (string, error)
• ToBase64DataWithQuality(imageQuality int) (string, error)
• SaveToFile(filepath string, quality int) error

PNGImageData

• Get() image.Image
• ToBytes() ([]byte, error)
• ToBase64() (string, error)
• ToBase64Data() (string, error)
• SaveToFile(filepath string) error

Validate the captcha

TIP

ok := click.Validate(srcX, srcY, X, Y, width, height, paddingValue)

Params	Desc
srcX	User X-axis
srcY	User Y-axis
X	X-axis
Y	Y-axis
width	Width
height	Height
paddingValue	Set the padding value

Click Shape Preview